The "common cause" is the name of a non-profit, non-partisan special interest group that serves as watchdog group to protect citizens from government corruption and influence peddling.
Step-by-step explanation:
A watchdog group located in Washington, D.C. and founded half century ago by a Republican named John W. Gardner and named it as "common cause". It's recognized for its hard work to combat the Vietnam War and reduce the voting age from 21 to 18 years.
It is described as non-partisan, and supports policy reform with the reformist campaign for good government. It condemns and vigorously lobbies modern-day attempts to contact for a convention under Article V to introduce changes to the Constitution of the United States from both progressive and conservative activists.